UNITED NATIONS: UN chief Ban Ki-moon is "deeply disappointed" that Myanmar's democracy icon Aung San Suu Kyi was handed another 18 months of house arrest and demands her unconditional release, his press office said Tuesday.

"The secretary general is deeply disappointed by the verdict in respect of Daw Aung San Suu Kyi (and) strongly deplores this decision," a UN statement said.

Ban called on Myanmar's ruling generals "to immediately and unconditionally release Daw Aung San Suu Kyi and to engage with her without delay as an essential partner in the process of national dialogue and reconciliation."

"Unless she and all other political prisoners in Myanmar are released and allowed to participate in free and fair elections, the credibility of the political process will remain in doubt," he added.

A Myanmar court convicted the 64-year-old opposition leader at the end of a marathon trial for breaching the terms of her detention by the ruling military junta, following a bizarre incident in which an American man swam uninvited to her home.

Judges sentenced Suu Kyi to three years of hard labor and imprisonment, but military ruler Than Shwe signed a special order commuting the sentence and ordering her to serve out a year-and-a-half under house arrest.

Last week, Ban, who is currently on home leave in South Korea, already urged Myanmar's rulers to free Aung San Suu Kyi and other political prisoners.

He made a similar call during a visit to Myanmar last month.

Suu Kyi has been kept in detention for nearly 14 of the past 20 years, since the military regime refused to recognize her National League for Democracy's landslide victory in elections in 1990.

Also last week, the UN secretary general said he had received no clear word from Myanmar's rulers as to when they plan to honor their pledge for an amnesty for some political prisoners.